A Chicago Police officer is accused in a federal lawsuit of beating a mentally disabled man and shoving his gun in the man’s mouth.

The lawsuit against Officer Matthew Jackson revolves around an incident between the cop and 19-year-old Nathaniel Taylor, who has a cognitive disability and an IQ of 44. The case is being pursued by his aunt, Oeinna Jackson.

The lawsuit, filed Friday, indicates the confrontation began when Taylor walked through the officer’s yard on Sept. 9, 2015. Jackson allegedly punched Taylor and knocked him to the ground before beating him and placing the gun in his mouth.

Taylor was arrested and charged with felony counts of aggravated battery to a peace officer and resisting arrest, as well as a misdemeanor count of trespassing, according to Chicago Police arrest records. He spent a week in the Cook County jail, according to the lawsuit. He was then released on electronic home monitoring.

The felony charges were eventually dropped, but Taylor pleaded guilty to the trespassing misdemeanor in April, according to Cook County Circuit Court records. He received three months of court supervision.